#include<stdio.h>
#include<time.h>
#include<math.h>
long add1(long n)
{
    long i,sum=0;
    for (i=1;i<=n;i++)
        sum+=i;
    return sum;
}
void AddTime1(long n)    
{
	clock_t t = clock();
	long sum = add1(n);
	t = clock() - t;
	printf("方法1:\n");
	printf("  结果:1~%d之和:%ld\n", n, sum);
	printf("  用时:%lf秒\n", ((float)t) / CLOCKS_PER_SEC);
}



long add2(long n)     
{
	return(n * (n + 1) / 2);
}


void AddTime2(long n) 
{
	clock_t t = clock();
	long sum = add2(n);
	t = clock() - t;
	printf("方法2:\n");
	printf("  结果:1~%d之和:%ld\n", n, sum);
	printf("  用时:%lf秒\n", ((float)t) / CLOCKS_PER_SEC);
}
int main()
{
	int n;
	printf("n(大于1000000):");
	scanf("%d", &n);
	if (n < 1000000)
		return(0);
        AddTime1(n);
	AddTime2(n);
	return(1);
}